JPH06200331A - Manufacture of sintered ore - Google Patents

Abstract

PURPOSE:To improve the yield of the whole sintered layer by exothermally oxidizing to melt-sinter the scrap having a specified value or less of the max. size. CONSTITUTION:The scrap of thin sheet iron, etc., produced in the iron-making work is sheared to the max. thickness of <=3mm and the longest side of <=50mm. The smaller the scrap size is, the better the heat conduction and the fusibility are. Blending ratio of the scrap is different according to the size of the scrap. In the case the max. thickness is <=1mm and the longest size <=20mm, the scrap can be blended to the max. 100%. Contrarily, in the large scrap having the max. thickness of <=3mm and the longest side of <=50mm, the scrap can be blended to the max. 70%. The scrap is dischaged from a scrap hopper 21 and charged to a surface layer 26 of sintering packing layer thorugh a feeder 24 and chute 25. Ignition is executed to this surface layer 26 by an ignition furnace 11, and while sucking the air downware, coke is burnt and the sintering material at the lower layer becomes high temp. and is sintered by oxidizing heat of the scrap.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sintered ore as a raw material for producing hot metal in a blast furnace or the like.

[0002]

2. Description of the Related Art FIG. 4 shows a schematic process of an example of a conventional method for producing a sintered ore.

Ore hopper 9 is the main raw material, limestone 8 is the auxiliary raw material, limestone hopper 8 is the auxiliary raw material, coke hopper 6 is the coke fuel, and return hopper 7 is the return mine. Wet granulate.

The sintering raw material 1 after the humidity-controlled granulation is once charged into the surge hopper 2 and then charged from the drum feeder 3 through the chute 4 into the pallet 12 to form the packing layer 5. The layer thickness of this filling layer 5 is 550 mm. The coke in the surface layer portion of the packed bed 5 is ignited by the ignition furnace 11, and while sucking air downward, 3.8% of the coke added to the sintering raw material is burned, and the combustion heat from the upper layer to the lower layer. The raw materials are sequentially sintered.

[0005]

According to the above-mentioned conventional method, the surface layer of the sintered packed layer immediately after exiting from the ignition furnace has a high temperature air that has passed through the high temperature red heat part of the sintering progress zone like the middle layer and the lower layer. As a result, the coke does not burn, but cold air in the atmosphere is sucked to burn the coke, so the temperature does not rise, and it is not sufficiently sintered, resulting in a sintered ore with low strength. Further, since the surface layer of the sintered packing layer is not well sintered, the sintering of the layer below the surface layer of the sintered packing layer is also adversely affected, and the yield is reduced. For this reason, there is a problem in that fine particles are increased during crushing and sizing, and the yield (yield) of products of 5 mm or more decreases.

[0006] As a solution to this problem, a method of supplying a large amount of fuel coke to the surface layer before ignition to solve the heat shortage of the surface layer is disclosed in Japanese Patent Laid-Open No. 60-140087. The effect corresponding to the increase in the amount of coke does not appear, the yield improvement is small, and it cannot be said that the problem has been solved sufficiently. Further, according to the pressing method from the upper surface of the surface layer sintered ore after leaving the ignition furnace described in JP-A-61-9526, most of the surface layer of the sintered packing layer is not sintered at the time when the pressing is started. Since it has been completed, the effect on the surface layer is small and the yield improvement effect is small.

The present invention solves the above-mentioned problems, improves the yield of the surface layer of the sintered packing layer, and also has a favorable effect on the sintering of the lower layer, thereby improving the yield of the entire sintered layer. An object of the present invention is to provide a method for producing a sintered ore.

[0008]

The gist of the present invention is as follows.

The surface layer of the sinter packed layer of the downward suction type sintering machine is charged with flaky iron scrap or a mixture of flaky iron scrap and a sintering raw material so as to have a thickness of 10 mm or more and 200 mm or less, and then the surface layer is ignited. A method for producing a sintered ore, which comprises sintering while sucking air downward.

The maximum thickness of the flaky iron scrap is 3
mm or less, and the longest side is 20 mm or less, The manufacturing method of said sintered ore characterized by the above-mentioned.

The maximum thickness is 1 mm or less, and the longest side is 20
The method for producing a sinter as described above, characterized in that the flaky iron scrap having a size of not more than mm is mixed with the flaky iron scrap with 1 to 100% of the total weight of the sintering raw material.

The maximum thickness is 3 mm or less, and the longest side is 50
The method for producing a sinter according to claim 1, wherein the flaky iron scrap having a size of not more than mm is mixed with the flaky iron scrap in an amount of 1 to 70% based on the total weight of the sintering raw material.

[0013]

According to the present invention, in order to solve the above-mentioned problems, thin iron scrap (hereinafter simply referred to as scrap) oxidizes and heats in the sintered layer to raise the temperature, and the scrap is well melted. Is used as a binder between particles to utilize the action of increasing the strength of the sintered body. Hereinafter, the present invention will be described in detail.

As the scrap, industrial wastes such as food and drink cans, scrap car iron plates, waste electric appliances, and iron flakes generated in steel mills can be used. In addition, as for the size of the scrap, it is desirable to use a flaky iron having a maximum thickness of 3 mm or less and a longest side of 50 mm or less in terms of heat transfer, and it is obtained by shredding. If the maximum thickness exceeds 3 mm and the longest side exceeds 50 mm, heat will not be transferred to the inside of the scrap and it will not melt sufficiently. Further, the smaller the scrap size, the better the heat transfer and the better the meltability, which is preferable, and there is no need to limit the lower limit of the size. The scrap may be compressed into a spherical shape or a square shape.

The scrap mixing ratio (scrap / scrap + sintering raw material) varies depending on the size of the scrap. If the scrap is small, the maximum thickness is 1 mm or less, and the longest side is 20 mm or less, it is possible to mix up to 100% at the maximum. On the contrary, if the scrap is large, the maximum thickness is 3 mm or less, and the longest side is 50 mm or less, a maximum of 70% can be compounded. This is because if the blending ratio of large scrap is large, the packing density of the packed bed becomes too large, heat transfer between solids becomes difficult, the solids do not melt sufficiently, and the strength of the sintered body cannot be maintained.

The thickness of the surface layer of the sintered packing layer is 10 mm or more 20
It is 0 mm or less. This is because the strength lowering of the sintered body is small from the surface layer of over 200 mm to the lower layer, and there is little room for improvement.
In the layer of less than 10 mm, the melt as a combined body is small,
This is because the amount of improvement is small.

[0017]

The present invention will be described below with reference to preferred embodiments.

[0018]

First Embodiment FIG. 1 shows a first embodiment of the present invention.

The filling layer 5 having a thickness of 520 mm was formed by a conventional method. Scrap having a maximum thickness of 1 mm or less and a longest side of 20 mm or less is cut out from the scrap hopper 21, temporarily stored as a scrap raw material 22 in a scrap surge hopper 23, cut out from a scrap drum feeder 24, and cut through a scrap chute 25 to a sintered packed bed. The surface layer 26 was charged in a thickness of 30 mm. The surface layer 26 of the sintered packed layer was ignited in the ignition furnace 11, and coke was burned while sucking air downward, and the raw materials were sequentially sintered from the upper layer to the lower layer by the combustion heat.

The heat of oxidation of the scrap of the surface layer of the sintered packing layer raises the temperature of the scrap and the sintering raw material of the lower layer to improve the melting property, and the yield of the conventional method shown in FIG.
It increased by 1% to 83.3%.

[0021]

Second Embodiment FIG. 2 shows a second embodiment of the present invention.

The scrap raw material 22 charged to the surface layer 26 of the sintered packing layer 70 mm is a sintering raw material having a thickness of 3 mm or less and a scrap having a maximum thickness of 3 mm or less and a longest side of 50 mm or less, and the scrap mixing ratio is 70%. .

As for the sintering raw material of 3 mm or less, the sintering raw material of 10 mm or less immediately after leaving the mixer 10 was extracted and classified by a vibrating sieve 27. The sintering raw material having a size of more than 3 mm and 10 mm or less was returned to the belt conveyor immediately before the mixer 10, and the packing layer 5 was formed by 480 mm by the conventional method.

Sinter raw materials having a size of 3 mm or less are mixed with scrap cut out from the scrap hopper 21 by the scrap raw material mixer 28, temporarily stored as scrap raw material 22 in the scrap surge hopper 23, cut out from the scrap drum feeder 24, and scraped into the scrap chute 2.
5 is charged onto the packed bed 5 through the sintered packed bed surface layer 26.
Of 70 mm was formed.

The surface layer 26 of the sintered packed bed was ignited in the ignition furnace 11 to burn the coke while sucking air downward, and the combustion heat was used to sequentially sinter the raw materials from the upper layer to the lower layer.

The surface layer of the sintered packing layer is heated to a high temperature due to the oxidation heat of scrap and the combustion heat of coke as a raw material for sintering, and the meltability of the lower layer raw material is improved corresponding to the surface layer. From the yield of 78.2% of the conventional method shown in FIG.
It increased by 4% to 85.6%.

[0027]

Third Embodiment FIG. 3 shows a third embodiment of the present invention.

The filling layer 5 having a thickness of 350 mm was formed by a conventional method. The scrap raw material 23 charged into the sintered packed bed surface layer 26 by 200 mm was a sintering raw material having a grain size of 10 mm or less, a maximum thickness of 3 mm or less, and a longest side of 50 mm or less, and the scrap mixing ratio was 30%.

As the sintering raw material having a particle diameter of 10 mm or less, the sintering raw material having a diameter of 10 mm or less immediately after leaving the mixer 10 was extracted.

Sintering raw material having a grain size of 10 mm or less is mixed with scrap cut out from the scrap hopper 21 by the scrap raw material mixer 28, temporarily stored as the scrap raw material 22 in the scrap surge hopper 23, cut out from the scrap drum feeder 24, and scraped. It was charged on the packed bed 5 via the chute 25 to form the sintered packed bed surface layer 26 of 200 mm.

The surface layer 26 of the sintered packed bed was ignited in the ignition furnace 11, and the coke was burned while sucking air downward, and the combustion heat was used to sequentially sinter the raw materials from the upper layer to the lower layer.

The surface of the sintered packing layer is heated to a high temperature due to the heat of oxidation of scrap and the heat of combustion of coke as a raw material for sintering, and the melting property of the lower layer of the raw material for sintering is improved corresponding to the surface layer. From the yield of 78.2% of the conventional method shown in FIG.
It was 8% higher and improved to 83.0%.

[0033]

INDUSTRIAL APPLICABILITY The present invention improves the meltability of the surface layer of the sinter-filled layer to improve the meltability of the surface layer of the sinter-filled layer, and also has a good effect on the sintering of the lower layer. Can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of the present invention.

FIG. 3 is a diagram showing an example of the present invention.

FIG. 4 is a diagram showing a schematic process of a conventional method.

[Explanation of symbols]

 1 Sintering Raw Material 2 Surge Hopper 3 Drum Feeder 4 Chute 5 Packed Bed 6 Coke Hopper 7 Return Mining Hopper 8 Limestone Hopper 9 Ore Hopper 10 Mixer 11 Ignition Furnace 12 Pallet 21 Scrap Hopper 22 Scrap Raw Material 23 Scrap Surge Hopper 24 Scrap Drum Feeder 25 Scrap chute 26 Sintered packed bed surface layer 27 Vibrating screen 28 Scrap raw material mixer

Claims (4)

[Claims] 1. A surface layer of a sintered packing layer of a downward suction type sintering machine is charged with flaky iron scrap or a mixture of flaky iron scrap and a sintering raw material so as to have a thickness of 10 mm or more and 200 mm or less, and then the surface layer is charged. A method for producing a sintered ore, which comprises igniting and sintering while sucking air downward. 2. The maximum thickness of the flaky iron scrap is 3 m.
The method for producing a sintered ore according to claim 1, wherein the length is 20 m or less and the longest side is 20 mm or less. 3. The maximum thickness is 1 mm or less and the longest side is 20 m.
2. The method for producing a sintered ore according to claim 1, wherein the flaky iron scrap of m or less is mixed with the flaky iron scrap in an amount of 1 to 100% with respect to the total weight of the sintering raw material. 4. The maximum thickness is 3 mm or less and the longest side is 50 m.
The method for producing a sintered ore according to claim 1, wherein the flaky iron scrap of m or less is mixed with the flaky iron scrap in an amount of 1 to 70% based on the total weight of the sintering raw material.